Finding and identifying device



March 22, 1960 K. L. SKOOG 2,929,882

FINDING AND IDENTIFYING DEVICE Filed Jan. 25, 19s? 2 Sheets-Sheet 1 1' N vszv TOR K 9R1. Iva/v Lew/ m?- J'kooc HWMW firronusrs March 22, 1960 K. L. SKOOG FINDING AND IDENTIFYING DEVICE 2 Sheets-Sheet '2 Filed Jan. 23, 1957 2,929,882 FINDING AND mENTIFYING DEVICE Karl Ivan Lennart-Skoog, Bandhagen, Stockholm, Sweden, assignor to Telefonaktiebolaget L M Ertcsson, Stockholm, Sweden, a corporation of Sweden Application January 23, 1957, Serial No. 635,775

Claims priority, application Sweden February 4, 19 56 3 Claims. (Cl. 179 -18) The present invention relates to a device for finding and identifying a marked, for example calling or idle circuit in a telephone system, wherein the marking is indicated by changing the polarity of one of a group of wires (single wire identifier). The wires are grouped to form a coordinate system. The coordinates may e.g. represent the units and tens digits, respectively, of the designations of the circuits. There are known numerous solutions of the identifying problem. The drawbacks .of these solutions are that in some cases expensive equipments or complicated and-circuits having three conditions for'operation or similar are required for selecting the desired line, and that in other cases (especially relay identifiers) a long time is required for identification.

The present invention is based upon delay lines, es-

pecially magnetostrictive delay lines and it affords a very inexpensive and reliable solution. The invention also permits the simultaneous identification of a plurality of calls. The device according to the invention can be designed for a varying number of circuits and with aid of different grouping methods. In the following embodiment of the invention showing a line identifier having 100 calling lines will be described and a suitable grouping plan has been selected, viz. a coordinate system having ten horizontal and ten vertical coordinates. The horizontal coordinates indicate the tens digit of the calling line (circuit) and calling line (circuit). At each cross point between the coordinates there is connected .a so called and"-circuit between the calling line and a reading wire, said reading wire being the horizontal coordinate and the outputs of said and-circuits being connected to the vertical coordinates. The condition for actuating the and-circuit is that the vertical coordinate receives a voltage when simultaneouslya call potential appearsand a voltage ap-. pears on the horizontal coordinate pertaining to the calling circuit. The identifier also includes a device for selecting one of a plurality of possible simultaneous calls.

The invention will be described more in detail in connection with the accompanying drawing in which:

Fig. la shows the principle of'a magnetostrictive delay line according to the invention.

Figs. lb-ld show embodiments of the and-circuits Fig. 2 shows an identifier for 100 calling circuits which is adapted for lock out.

Fig. 1a shows a nickel wire delay line N having the length 1, said said wire being provided with input coils S and S permanent magnets P P output coils M and M and amplifiers F -F The permanent magnets P are used for setting up a magnetic field in the nickel wire N. If an impulse is applied at the input A the winding S is actuated and thereby the magnetic field in the wire adjacent to S is changed. This field change generates an acoustic wave which propagates on one hand against Q and on the other hand against R. After .a time proportional to the distance between the input coil S;

and the output coil M the acoustic wave arrives at the output coil M and actuates the magnetic field there. An impulse is induced in from the output coil M, which impulse is amplified in the amplifier F If an impulse is appear also at the output coil M but at a later time which is determined by the distance between coils M and M 7 Fig. 1b shows an example of a basic and-circuit having two relay contacts K and K and a known out put U Fig. lc shows an electronicfequivalent having rectifiers 1 1 resistors R -R inputs E, F and a known output U and Fig. 1d shows an electronic equivalent comprising a resistor R4, a condenser C inputs G and H and an ouput U If a'sufficient voltage 1+ z=P is to be obtained at an output U a voltage is required at both the inputs G and H (Fig. 1d). The time-voltage diagrams above and below Fig. 1d show the voltage V; on the input G which is applied at the time-t the voltage V on the input H which is applied at the time t and the voltage V V; on the output U from the time t to Fig. 2 shows an identifier for a number of calling cit? cuits, comprising delay lines N N N3, amplifiers 1- ,,-F,,,,,v

V F -F G -F bistable circuits B 3 9, and"-circu,its 7 01-09 and Odd-O99, input CQilS -89 T1 andfT output coils M -Mzu resistors R' -R and condensers C -C comprised in the and-circuits and rectifiers L -L for preventing back current paths. The calling lines are grouped in ten vertical columns Vo-Vg and 10 horizontal rows Ho-Hg- Only the and-circuits Q 0 and 0 which are. of the kind shown in Fig. 1d, are completely shown.

The delay lines N and N are of the recirculating kind, that is, the last receiving coils M and M respectively are connected to the input coils T and T respectively. The timing of the pulses is controlled by clock pulses which by means of the and-circuits O and 0 respectively control the time position of the pulses on the delay lines N andN The and-circuits D and 0 are open only when pulses are present, both on the outputs from the .coils M and-M respectively and the clock pulse line. The fed back pulses are amplified by amplifiers F and F respectively.

The operation of the identifier is as follows:

When an impulse is recirculating in the delay line N the receiving coils M to M are sequentially generating. output pulses as the acoustic wave is passing the coils. The distance between the coils is such that the time ink terval between the pulses on adjacent coils is for instance 100 microseconds. When an impulse for example is: emitted from the coil M it is amplified by the amplifier 6,, and applied to the horizontal conductor H which is connected to the condenser input of all the and-cireuits of the ninth row, that is, the and-circuits pertaining to the subscribers N 90-99. The subscribers are each provided with a switch contact which is connected to a positive potential when the subscriber is calling, but is otherwise connected to a negative potential. In the drawing only one of the subscribers, namely N 99 is shown in the calling state and therefore only the output of the and-circuit 0 will generate an impulse as the contact K is the only in the ninth row which is connected to a positive potential. This impulse is applied to the colunm conductor V and via the amplifier F to the input coil S, on the magnetostrictive delay line N An acoustic wave is caused in the magnetostrictive line which propagates along the line to the coil M The time delay between consecutive input coils on the delay line N is a fraction of the time delay between consecutive output coils on the delay line N If, as is shown in the drawing, the delay time between consecutive coils on the delay line N is IOO microseconds, the delay time between consecutive coils on the delay line N is selected t b t n s w s er ten vert cal conduc o V to V The distance d; between the last input coil and. the output coil M is in the embodiment selected to be 100 microseconds. If pulses are simultaneously applied to all the vertical conductors V V they will thus be received ten microseconds separated during the time. interval 190 to 19.0 microseconds after the pulse is applied. Thus the impulse which was applied to the horizontal conductor H thousand microseconds after the same impulse was generated by the input coil T will arrive at the output coil M20 eleven hundred microseconds; after the scanning. pulse was initiated by the coil T By means of the at enuated l e i a s co dn lss our w th its. uest O ned Wh t e p lses. ata iaeeu out:

puts are ten microseconds; tima displaced, As is IIl$Il1 tioned above, the recirculation on the delay line N is controlled by the same clock pulses which control the recirculation on the line N and thusleach of the pulses which arrive at the output coil Mac will be, in phase with. one impulse obtained from one of the outputs of the delay line N Thus the impulse. originating from the an -circuit 99 will be in phase with thepulse of the coil M The latter pulse is after amplification. in. an amplifier F applied to one input ofan and-circu it 0 the other input of which is connected to the output coil M When the impulses; from M and, M are coin-v cident a trigger pulse is obtained firorn the output of the and-circuit- 0 which triggers the. bistable circuit B indicating the units digit "9 of the calling subscriber. When the circuit 13 has operated an output voltage is obtained therefrom on the wires which. is applied to. one input of the and-circuits O to O Said output voltage, however, does not appear until the next pulse has been emitted frotn the output coil M and thus said pulse does not open the and"-circuit 0 However, when the impulse through the delayline N arrives at the output coil M both the impulse. of, the and--circuit 0 are conditioned for passing an impulse to the'output. The output pulse. of the. and-circuit O triggers the bistable circuit B which indicatesthe ten digit of the calling subscriber. Now both the digits of the calling subscribers number are identified. In order to prevent more than one subscriber from being identified at one time and to prevent false identifications an inhibit circuit (not shown) may be arranged which prevents more than one output pulse from the output coil M from triggering more thanone of the bistable: circuits B -B at a time; In the same way precautions may be taken such that only-one of the bistablecircuits B -eB can be operated. Thus only one nt the bistable circuits B0-B1g. and one ofthe bistable circuits; B 13 can be operated; during one and the same identification operation until the inhibit condition is removed after a completed identification.

By means of arranging additional. suitably spaced output coils on the delay line N further identification o erations can be made simultaneously.

The invention is applicable not only to line identifiers, but it can as well be applied in other circuits for finding and identifying calling or idle circuits, particularly in electronic telephone systems.

I claim:

1. In a devicefor finding and identifying a marked circuit element among a plurality of similar elements, in combination, rows and columns of conductors forming a coordinate system, a coincidence circuit individual to each element and having at least two inputs and one output at each cross point between a row conductor and a column conductor, the column conductor being connected to the output and the row conductor being connected to one input, the second input of each coincidence circuit being connectable to a source of marking potential in the respective circuit element, means for sequentially applyins; mutu llyime, isplaced scanning pulses ta said row conductors causing a pulse. at the outputs. of the coin- QidQiiQc circuits having a. markingv potential on the second input, a delayline having a plurality of equally spaced inputs, each connected to one of the column conductors and at least one output for separating pulses simultaneously applied to said column conductors in time, the delay time between the first and last input on saiddelay line being less than the interval between successive. scanning pulses, and means for separating at least one of the time distributed, pulses; appearing on, said. output by. means of coincidence with a, selection'signal. having the corresponding time position.

2. A device as claimed inclaim '1. wherein said means for separating at least, one of the. time distributed pulses appearing on the output of the delay line comprises a cyclically operating recirculating delay line. having the samenurnber of equally spaced outputs. asthe number of column conductors, the per-iod'of said pulse source being completed during the interval between consecutive scanning pulses, a. two input coincidence. circuit for each.

phase output having a first input. connected to the. delay line output and the second input, connected to the pertaining phase output, and bi-stable. circuit means eachv indicating a column containing a marked element, the output of the last mentioned coincidence circuits being each connected to. a respective one of said indicating devices.

3. Adevice asclaimedin claimlland comprising means for indicating coincidence. betweenv the scanning pulses and the operation ofjany oflsaidi bi stable circuit'means, second bi-stable circuit means each indicatinga row containing a marlgedelement, eachjof saidrnean's beingconnectedtoia respective one of said second bi-stable circuit means.

Barlow et a1. June 5, 1956 Barlow et al. Oct; 1, 1957 

